1. Field of the Invention
The present invention relates to an image recording apparatus in which photo curable ink is discharged on a recording medium to record an image on the recording medium.
2. Description of the Related Art
Recently, an ink jet recording method has been applied to various printing fields such as a special printing or the like, that is, a photograph, various printing, marking, color filter and the like, because an image can be produced easily and at low cost compared to the gravure printing method. Particularly, in the ink jet recording method, a combination of an ink jet printer which discharges and controls small dots, an ink with improved a color range, durability, aptitude for discharging ink and the like, a specific paper having dramatically improved ink absorptivity, coloring property of coloring material, surface gloss and the like is successful in obtaining image quality comparable to a silver salt photograph.
The above described ink jet printer can be classified by the types of inks. That is, there are a phase-change ink jet method using an wax ink which is solid at room temperature, a solvent-based ink jet method using an ink containing a quick-drying organic solvent as a main component, a photo curable ink jet method using a photo curable ink which is cured by photo irradiation such as irradiation with ultraviolet rays or the like. Among them, in the photo curable ink jet method, relatively less odor is produced in comparison with the other recording methods, and an image can be recorded even on a recording medium having no quick-drying property and ink absorptivity other than the specific paper, so that much attention has been paid thereto.
Such photo curable ink jet printer is provided with a recording head for discharging ink as small ink droplets onto a recording medium and light sources for radiating light on a carriage, and the carriage is moved over the recording medium with the light sources on to irradiate the ink just placed on the recording medium with light to immediately cure the ink (for example, refer to JP-Tokukai-syo-60-132767A).
In the above described ink jet printer of the photo curable ink jet method, there is a case that the light sources do not radiate light uniformly due to adhesion of ink mist or foreign matter such as dust or the like on the light sources in an image recording operation or the like. In this case, a portion where light with appropriate irradiation energy is not radiated may be generated, thus, failing to record an image of good quality. Especially, when the illumination intensity of a portion of the light source significantly decreases to generate an illumination intensity decreased portion in which the illumination intensity is less than the specified illumination intensity, the ink placed on the portion of the recording medium corresponding to the illumination intensity decreased portion is not irradiated with light having sufficient irradiation energy, thus, the ink may not appropriately be cured at the portion.